Winches are widely used for a wide variety of purposes when it is necessary to apply a tensile force. Although many winches are stationary they are also mounted on movable vehicles and portable equipment. The winches most widely used generally have a single drum on which a rope or wire rope is wound and then unwound as required by the use to which it is put. There are some uses, however, which require that a winch have at least two drums, with each drum carrying a separate rope or wire rope.
Knox U.S. Pat. No. 4,012,001 discloses a type of winch for reeling and unreeling wire for aerial spinning of suspension cables for a suspension bridge. It discloses two separate reels or drums which can rotate at different speeds. It also shows a level winding mechanism for each reel or drum which use separate drives and which are not synchronized one to the other so that the two reels are not necessarily level wound simultaneously.
Selby U.S. Pat. No. 2,968,446, although not directed to a winch, discloses a tube which reciprocates on a rod. The tube carries two sliver guides so that when the tube reciprocates the sliver is wound onto two separate spools rotated by frictional contact with a drum.
The described mechanisms upon careful study are not seen to be suitable for the controlled level winding of two ropes on different drums simultaneously followed by controlled level unwinding of the ropes from the drums. There is accordingly a need for such a winch apparatus, especially for use in luminaire assemblies movably mounted on a tall mast or pole.